Mass flow controllers (MFCs) automatically control the flow rate of a gas in accordance with a desired flow rate input into the MFCs, typically as an electric signal. Various types, or configurations, of MFCs are available, some of which rely on heat transfer to determine a flow rate of incoming gas. Others rely on a small hole, also referred to as an orifice, formed in a plate through which gas passes to produce a measurable pressure difference.
While these and other types of mass flow controllers are adequate for many applications, including traditional semiconductor device fabrication applications, they are increasingly unsuitable for semiconductor device deposition processes and etch processes that deliver gases to process chambers for advanced semiconductor fabrication processes. These advanced processes often produce features having line widths on the order of 20 nm or less. To improve processing of such features, particularly when multiple semiconductor wafers are processed simultaneously in different chambers or stations, flow control provided by conventional MFCs may need to be improved. Each MFC in a system should control gas flows identically and with a high degree of accuracy.